The numerical difference between the two groups in prepartum concentrations of vitamin A, and partly, vitamin E, are likely related with the dry matter intake which was higher in OF vs. RE prepartum. The concentration of vitamin E tended to be lower after +14 days relative to parturition in Chloroprocaine hydrochloride despite the lack of difference in feed intake postpartum. The markedly greater plasma creatinine in RE vs. OF prepartum was striking. Creatinine is considered an index of muscle mass and/or renal function. In our case the greater concentration of creatinine in RE cows prepartum was not due to greater muscle mass because it decreased in proportion to the body weight when cows were energy-restricted. An increase of plasma creatinine due to feed restriction have been observed previously but not always. A greater creatinine concentration in blood despite a lack of increase in muscle mass has been explained by a decrease in renal filtration and/or by an increase in muscle proteolysis. In our study it is likely that RE cows had an increase in proteolysis due to a reduction in MS436 body weight. This is supported by previous data from dairy cows where an increase of plasma creatinine was observed immediately before and after calving when proteolysis normally increases. Creatinine also can be produced by the liver. In our microarray we measured the expression of genes coding for 2 out of 3 enzymes involved in the formation of creatine phosphate from glycine and arginine, the guanidinoacetate Nmethyltransferase and the creatine kinase, mitochondrial 1B. The former was numerically and the latter was significantly more expressed in RE vs. OF cows. However, the higher glucose and insulin prepartum in OF vs. RE are indicative of a decrease in insulin sensitivity; in rats, insulin resistance has been associated with decreased liver glycogen content. Therefore, the cause for the response in gene expression observed might be due to the contrasting effect of higher insulin but also insulin resistance. The AA can play an important role during early lactation to meet the glucose requirements through hepatic gluconeogenesis.